ARLINGTON, Va. (WUSA) -- We're learning about a disturbing sexual assault that took place in Arlington over the weekend.

The victim's disability created an unusual challenge for investigators.

Police say the victim in this case is a woman in her 20s who is deaf and does not know American sign language. So investigators had to write down their questions for the traumatized woman and wait for her to write out her answers.

"She was dropped off by a cab at the Rosslyn Metro station, where she went underground to catch a Metro back to her residence in Alexandria," said Dustin Sternbeck, spokesman for the Arlington County Police.

In the early hours of last Saturday morning, the victim was returning to Virginia after a night out in DC.

"Upon learning that the Metro wasn't going to arrive in a short amount of time, she resurfaced to street level, attempted to find a cab again drive her back to her residence, and was grabbed and pulled into an alley by the suspect," said Sternbeck.

The deaf-mute victim was especially vulnerable at a time of day with few witnesses or people to come to her aid. But police say she put up quite a fight.

"When the suspect initially grabbed our victim, he placed his hand over her mouth. The victim was able, actually, to bite his hand. And fought him off during the entire process and was able to get away," said Sternbeck.

Investigators are looking for any surveillance cameras in the area in hopes of identifying their suspect.

So far, the description of the suspect is very vague: he's black, was wearing all grey clothing, and appeared to be homeless.